Black light, battery/generator powered, complete novice

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BlindSpot

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Greetings,
My name is Andie/BlindSpot and I want to begin by saying I don't speak tech (yet) and simple vs. detailed explanation answers are the best place to start for me. I'll work my way into more complicated. :eek:

Project: need to light up students' art piece in field with u/v lights (black lights or equivalent).
Prefer LED lights, strip?, which will be powered by generator or preferably battery we can charge with generator during the day.
Length: 16-32 feet

Questions:
1. do you know which color(s) of LED strip lights will produce reactions from u/v reactive pigments? (Typically I search through Amazon- some specifically list that they are equivalent to black lights - and some comments suggest that all blue or purple will work.)
2. What are the battery powered options for this type of project (in my vocabulary I think golf cart battery, car battery, super marine battery, generator, etc... As long as I can look it up I don't care what it's called! Lol)
3. I'm guessing it will depend on the battery to determine what I would need to connect the lights to the power source? If I were to make a list of materials required in order from the battery to the light strip what would they be? In general? I realize there's many variables involved.

Most of my students are proficient in soldering and tech stuff but I want to learn- I don't want to always depend on someone else. I will however, assemble any of this at Craft Night with my friend Talik and co. who are probably pros at thus stuff!

Thank you in advance- I appreciate your time and patience!

BlindSpot
 
Depends on the effect you want. A 400 nm LED will make most UV pigments glow, but will also be a very visible purple color. A 380 nm LED will be less directly visible and a 365 nm LED even less visible, but you'll get less power output from it, so for a given drive current the UV pigments will (probably) be less bright. I've used these types of LEDs but not for your application so you'll probably just have to try it and see. If you type in "UV flashlight" to ebay you'll see options starting under $10, and individual 3-watt 400 nm LEDs are even less than that, you just need to put the right drive current into them.

If you prefer a strip of UV LEDs, here's an example (one of many):
http://www.ebay.com/itm/12V-3528-39...ed-m-120led-m-Strip-black-light-/291659953822

That one appears to have current-limit resistors built in, so you can simply apply 12 V DC from any source (power supply or 12V battery) that can deliver enough current (1 Amp per meter of strip length) and it will light up. So if you wanted a 15 foot long strip, that is about 5 meters so you'd need 12V at 5 amps.

By the way, as you mentioned outdoor use- on that item, the title mentions "waterproof" but the description says "non waterproof" (!)

some others offer a waterproof version (must select that option in menu)
http://www.ebay.com/itm/Black-PCB-U...-400nm-Purple-Waterproof-12V-DC-/351488635046
 
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Note that most transparent plastics will attenuate the UV Light (Filter it out so it doesn't pass through)
I'm not sure how well it will work with the waterproof silicone tube many light strips supply.
Also best if lamp enclosures or artwork enclosures are glass. (note that some specialty glasses are designed to filter out the UV)
 
Those 12V LED strips look like a pretty good option, if you're ok with lot of blue light. If you want the really "black" light, you'll probably need to look for much more expensive 365 nm LEDs.

For a 15 foot long strip, that's 5 amps of current. You'll need a pretty big battery!

Battery capacity is rated in amp-hours. If your battery has a 20 AH capacity, that means it can power something using 1 amp for 20 hours, or something using 5 amps for 4 hours. But there are a couple caveats...

Generally 2 things tend of ruin batteries. Overcharging is the worst. But "deep discharge" is also pretty destructive. When a battery is called "deep cycle", that means it's meant to be able to run all the way down to about 5%, maybe even 2% or 1% remaining charge. Car batteries are optimized for massive short-duration output to start your car engine, and of course a trade-off in their design is they're not meant to discharge so far. Usually those batteries have a rating for how many amps they can delivery but they don't have an AH rating for total capacity. When you're looking for a battery, that's a sure sign it's meant for this sort of use.
 
I see several Chinese sellers have (supposedly) 365 nm 10W LEDs. They look pretty awesome, might get a couple to play with.... ;)

http://www.ebay.com/itm/10W-High-Po...M-385nm-395nm-410nm-Ultra-Violet/251921966541

These will give a lot of light in just 1 spot, so probably not the best for lighting up a long area. These raw LEDs must not be connected directly to a battery. You have to use a resistor or some sort of circuit to control the LED's current. Those LED strips have resistors, but a raw LED like this does not. These really high power ones also need to bolt to a piece of metal to dissipate heat. The little ones in strips don't heat up as much, and usually the strip is a material that helps remove the heat from the little LEDs.
 
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PaulStoffregen said:
I see several Chinese sellers have (supposedly) 365 nm 10W LEDs. They look pretty awesome, might get a couple to play with.... ;)
Click to expand...

DANGER WARNING!
Playing with 10watt 365nm UV LEDs can be dangerous.
A high quality 365nm LED is completely invisible to the human eye.
But that power level would be very damaging to your eyes.
Be sure to wear UV eye protection when messing around with these
 
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